Such belts which are generally planar have many uses as conveyor belts or also as drive belts. In this instance, in particular the edges at the longitudinal edges of the extended belts are subject to a high mechanical load and stress during use, so that the peripheral edges of the belt are often unprotected against environmental influences with prolonged use and can be penetrated by particles of dirt and germs. This is unacceptable in all commercial fields involving the production, processing and sale of foodstuffs, in particular with regard to good hygiene practice and the HACCP concept (Hazard Analysis and Critical Control Point).
DE 1 237 768 discloses a production method for conveyor belts, wherein a carrier strip with a material strip adhesively-bonded thereto is moved towards and placed around an edge of a belt. Subsequently, the elastomer of the material strip is melted and formed by pressing heated plates on the upper and lower side of the conveyor belt. The basic notion of this invention involves fitting additional elastomer material at the edge of the conveyor belt and bonding it into a unit with the elastomer material of the conveyor belt under the action of temperature and pressure.
DE 1 289 300 discloses a conveyor belt which has a core with tensile strength comprising a plurality of woven fabric inserts which are connected by means of connecting layers of thermoplastic material. The warp threads of the woven fabric insert comprise, in the edge zones of the fabric, a thermoplastic material which melts under the action of temperature and pressure and bonds to form a unit with the thermoplastic material of the connection layers. However, these thermoplastic warp threads have a low level of tensile strength with the result that they are undesirable in practice. Such warp threads are therefore often used only with specific spacing, so that the edge in this region can be separated which, however, makes flexible production completely impossible.
GB 1,030,354 and U.S. Pat. No. 5,244,083 describe methods wherein conveyor belts comprise a plurality of layers, which have different widths in the peripheral regions. The widest peripheral layer is folded around the other material layers. However, with belts which are produced in this manner, it is also possible for the multilayer structure to become delaminated or frayed.